This invention relates to the field of electrophotography, and more particularly to a dual mode electrophotographic apparatus which can be selectively operated in a copy mode, to copy an original document, or in a print mode, to form a document from an electrical-data-defined image. More specifically, this invention provides a raster scanning mechanism, for example a laser, which is operable in both modes of operation. In the copy mode, the scanning mechanism erases an area of the photoconductor exclusive of a working area into which the image of the original document is reflected. In the print mode, the scanning mechanism erases the entire photoconductor exclusive of the data-defined image.
While dual mode electrophotographic copier/printers are known, it is not known to make double use of the raster scanning mechanism to border-erase in the copy mode, and to total-erase in the print mode.
In addition, electrophotographic copiers are known wherein a working portion of a photoconductor is illuminated by the reflected image of an original document, and wherein the remaining portion of the photoconductor is illuminated, or erased, by light sources which are provided for only this purpose.
The present invention eliminates the need for such erase light sources by the dual utilization of the printer raster scanning mechanism to record print information when in the print mode, and to discharge the photoconductor bordering the reflected original document image when in the copy mode.
The foregoing and other features and advantages of the invention will be apparent from the following more particular description of a preferred embodiment of the invention, as illustrated in the accompanying drawing.